Chapter 18- Respiration Flashcards
Where does the link reaction take place?
Mitochondrial matrix
Where does glycolysis occur?
Cytoplasm
Where does oxidative phosphorylation happen?
Inner membrane
Where does kerbs cycle happen?
Mitochondrial matrix
Why does aerobic respiration yield fewer molecules of ATP than the theoretical maximum?
- some ATP used to actively transport pyruvate into mitochondrion
- some energy released in ETC is not used to transport H+across inner membrane but released as heat
- not all H+ movement is through ATP synthase
Why anaerobic respiration produces less ATP than aerobic respiration?
- oxygen not available as final e- acceptor. Oxidative phosphorylation does not occur
- only substrate level phosphorylation occurs
- glycolysis- which is conversion of glucose to pyruvate. This produces net 2 molecules of ATP
Anaerobic respiration in animal cells can be reversed. Yeast cells can’t be reversed. Why?
-in animals: pyruvate reduced to lactate. Can be reversed as no atoms lost. Lactate dehydrogenase available to revise reaction
In yeast: pyruvate converged fo ethanol + CO2. Cannot be reversed as atoms are lost
Glycolysis?
- phosphorylation of glucose does forming hexose bisphosphate
- splitting into triode phosphate
- Pi added to form triose bisphosphate
- dehydrogenation to form reduced NAD
- 4 phosphate removed so total production of 4 ATP
- pyruvate produced
Why lactate converted into pyruvate by hepatocytes rather than by respiring cells in which it is produced?
- hepatocytes can tolerate low pH
- conversion of lactate requires O2 + muscle cells don’t have enough O2
What would happen is the conversion of lactate to pyruvate was inhibited?
-build up of lactic acid. Could denature proteins due to low pH
Where in the liver excess reduced NAD can be oxidised to NAD?
Inner mitochondrial membrane
Reaction that removes phosphate group from ATP molecule?
Hydrolysis
Alcohol fermentation. Hydrogen acceptor?
-ethanal
Alcohol fermentation. Intermediate compound?
Ethanal
Alcohol fermentation. Products?
Ethanol
CO2
Alcohol fermentation. Why this is important?
- Releases NAD to accept more H so glycolysis can continue.
- ATP available for protein synthesis, DNA replication etc
When CO2 is produced?
- oxidative decarboxylation (link reaction)
- kerbs cycle
Why there is an increased rate of respiration at higher temp?
- have more KE
- more ESC formed.
- respiratory enzymes involved
Why higher rate of respiration in soaked seeds than dry seeds?
- enzymes + substrates can move in soaked seeds
- movement prevented in dry
- soaked seeds require more ATP
Name of hydrogen acceptor in lactate fermentation?
Pyruvate
Benefit of anaerobic respiration?
- ATP produced
- recycles NAD so can be used again in glycolysis
- glycolysis continues
Products of oxidative phosphorylation?
- ATP
- H2O
- NAD
- FAD
Role of coenzymes in respiration?
- NAD + FAD accept H and be reduced
- reduced NAD + FAD supply e- to e- transport chain for oxidative phosphorylation
- reduced NAD + FAD supply H+ to e- transport chain for chemiosmosis
- CoA carries Acetyl group to krebs cycle
Role of ATP?
- universal energy currency
- phosphate can be removed by hydrolysis to release energy for metabolism
Pyruvate doesn’t proceed to link reaction in anaerobic respiration. What happens in an animal cell and importance of this reaction?
- pyruvate converted to lactate
- catalysed by lactate dehydrogenase
- pyruvate accepts H from reduced NAD
- NAD regenerated
- allows glycolysis to continue
- some ATP can be produced
Importance of anaerobic respiration?
- pyruvate loses CO2 to form ethanal. Catalysed by pyruvate decarboxylase
- reduced NAD giving H to ethanal
- NAD regenerated so glycolysis continues
What would happen if pyruvate not transferred to mitochondria efficiently?
- less pyruvate for link reaction + krebs cycle
- no oxidative phosphorylation
- less ATP resulting in muscle weakness
- anaerobic respiration takes place
- lactate results in lower pH which causes aching muscles
Parasites live in blood. Blood carries O2 but parasites still respire anaerobically. Why?
- O2 is binded to haemoglobin
- haemoglobin has higher affinity for O2 than parasite
What is given off from pyruvate to ethanal?
Co2
What happens when ethanal turns to ethanol?
Reduced NAD turns to NAD+
glycolysis, Krebs cycle and Calvin cycle involve triose phosphate. How do they work independently from each other?
- take place in diff parts of cell
- glycolysis in cytoplasm
- Calvin cycle in stroma of chloroplast
- Krebs cycle in mitochondrial matrix
How endothermic animal prevents its body temp from decreasing when external temp decreases?
- peripheral thermoreceptors stimulated by decrease in external temp
- impulses sent to hypothalamus
- vasoconstriction of arterioles to reduce heat loss by conduction
- shivering. Involuntary muscle spasms to generate heat
- erector muscles contract to raise hair to trap an insulating layer of air
How does NAD act as a coenzyme?
- accepts H and is reduced
- supplies H to ensyme involved in later stage of respiration
Why are H+ actively pumped across the membrane?
To increase concentration gradient
Why do H+ ions diffuse down ATP synthase ?
- membrane is impermeable to ions
- ATP synthase provides hydrophilic channel
Why e- released from FAC lead to synthesis of less ATP than e- released from NAD?
- reduced NAD releases e- to carriers at start of ETC
- reduced FAD releases e- to carriers after the start of ETC
- FAD e- are transported for a shorter distance so fewer protons actively transported
Why yeast cells are facultative anaerobes?
- normally respire aerobically
- can respire anaerobically when needed
Respiration pathway of triglycerides?
- broken down into glycerol + fatty acids
- fatty acids under do beta oxidation forming acetyl groups
- acetyl groups are taken into Krebs cycle by CoA
- glycerol converted to pyruvate
Process of chemiosmosis?
- occurs in mitochondria
- involves matrix and inner membrane
- ATP synthase embedded in membrane
- H+ ions pumped out of matrix into membrane space
- proton gradient created
- H+ ions diffuse through hydrophilic transmembrane protein from area of high concentration to area of low concentration
- ATP synthase produces ATP from ADP + Pi by proton movement force
Production of ATP by substrate level phosphorylation?
- 2 ATP molecules per glucose from glycolysis
- this is when triose bisphosphate is broken down to pyruvate
- 4 ATP made in total. 2 used
- 1 ATP produced per turn of Krebs cycle when 5c compound converted to 4c compound
How the structure of galactose allows it to be used as a respiratory substrate?
- bonds contain energy so bonds can be broken by respiratory enzymes
- soluble so can move within cell
- OH/H groups so can form H bonds with water
Name of H acceptor after glycolysis in mammal anaerobic respiration?
pyruvate
Name of H acceptor after glycolysis in yeast anaerobic respiration?
ethanal
benefit of anaerobic respiration?
- ATP produced
- reclyes NAD so NAD can be used again
- allows glycolysis to take place
Role of coenzymes in lead cell?
- NAD/ FAD/ NADP can accept H and be reduced
- reduced NAD/FAD supplies e- to ETC in oxidative phosphorylation
- reduced NAD/FAD supplies H+ for chemiosmosis in oxidative phosphorylation
- reduced NADP supplies H to calvin cycle
- coenzyme A carries acetate to Krebs cycle
How emphysema (shortness in breath) could result in fatigue?
- less ventilation
- less O2 for oxidative phosphorylation in aerobic respiration
- less ATP produced
A: peas B: glass bead + peas C: glass beads.
Why B has some glass beads.
respirometer?
- to make vol the same in respirometers
- as without beads there woul be more O2 in B
Why increased rate of respiration at 25c compared to 15c?
- at higher temp there is more KE
- increased activity of respiratory enzymes e.g dehydrogenases
Reason for difference in rate of respiration between soaked and dry seeds?
- higher in soaked
- movement of reactants limited in dry seeds
- soaked seeds need more ATP bc they have an increased metabolism compared to dry
What happens at glycoloysis?
- phosphorylation of glucose by ATP forming hexose bisphosphate
- splititng into triose phosphate
- free inorganic phosphate ions present in cytoplasm phosphorylate forming triose bisphosphate
- dehydrogenation. reduced NAD formed. pyruvate produced. 4 ATP molecules formed in total
Why overwatering can kill plants?
- water fills air spaces in soil
- prevents O2 reaching root hair cells
- no O2 so aerobic respiration cant occur
- no link reaction/ krebs cycle/ oxidative phosphorylation
- bc no oxygen to act as final electron acceptor
- plant switches to anaerobic respiration
- only glycolysis occurs
- alcoholic fermentation occurs
- pyruvate to ethanal. catalysed by pyruvate decarboxylase. produces CO2
- ethanal to ethanol. NAD regenerated.
- ethanol is toxic
- less ATP produced/ only 2 from glycolysis
- less active transport
- less photosynthesis
